BobMackay

5 ms·

1. 1.▲
   by BobMackay 3y ago

   I think one should also consider the failure modes when, for example, a tree falls into the wall. For a straight wall, it is possible that a falling section will propagate the failure along the entire length of the wall. For a wavy wall,
2. 2.▲
   by BobMackay 3y ago

   I understand equations, both the simple and quadratical!
3. 3.▲
   by BobMackay 3y ago

   I have been waiting for this for 50 years! It is wonderful that Roger Penrose and my father, Alan Mackay, are still alive to see it! If only Escher could see it!
4. 4.▲
   by BobMackay 4y ago

   Thanks. My copy was actually the copy that they sent to J.D. Bernal, and was signed over to him "with the compliments of the authors". My father was another PhD student of Bernal's, and became Professor of Crystallography a
5. 5.▲
   by BobMackay 4y ago

   Here is their 1947 paper on Principles and Progress in the Construction of High-Speed Digital Computers: http://bobmackay.com/Booth/Booth.html
6. 6.▲
   by BobMackay 4y ago

   I was present at the BMUG meeting on Berkeley campus when Andy demonstrated Switcher for the first time. He did no talking, but simply ran up two or three applications... and then the whole screen scrolled sideways and the audience was on
7. 7.▲
   by BobMackay 6y ago

   If you like such things, Nguyen Duc Thang has a ridiculously extensive collection he has been modeling, which can be seen at https://www.youtube.com/user/thang010146/featured .
8. 8.▲
   by BobMackay 7y ago

   The notion of "Programming" was mentioned and even defined in 1947 by Donald Booth. See http://bobmackay.com/Booth/Booth.html Principles and Progress in the Construction of High-Speed Digital Computers. &quo
9. 9.▲
   by BobMackay 8y ago

   I don't have a 3d printer - Shapeways is much more convenient and cheaper!
10. 10.▲
    by BobMackay 8y ago

    It is a BlueChick, from BuildYourCNC. I recommend it if all you wish to cut is wood. It is not really stiff enough for aluminum. A great starter machine. Mine is starting to wear out the rails, so I am in the course of building a new on
11. 11.▲
    by BobMackay 8y ago

    My father (Professor Alan Mackay) and I visited Professor Penrose in Oxford in 1975, to discuss his new tiling pattern, and I was able to write a computer program (in Algol 60) to draw it on a graph plotter. See http://bobmackay
12. 12.▲
    by BobMackay 9y ago

    Just as a heads up, if you try to run this program with your monitor in portrait mode, the program defaults to full screen mode, but assumes a landscape monitor. The parts that are cut off are critical to getting the program to do anything
13. 13.▲
    by BobMackay 9y ago

    This counting-out game is known as the Josephus Problem, and dates back many centuries. See https://en.wikipedia.org/wiki/Josephus_problem . I have a wood-block printed Japanese textbook from around 1700 with a good
14. 14.▲
    by BobMackay 9y ago

    Just for completeness, the 1990 paper referred to was by my father, Professor Alan Mackay, and was published in Modern Physics Letters B, Vol 4, No 15. I have put up a roughly scanned copy at http://bobmackay.com/Alan/